JP2008002586A - Method of manufacturing rotation-linear motion converting mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a rotation-linear motion converting mechanism capable of suppressing the inclination of planetary shafts and being adapted to a variety of structures thereof. <P>SOLUTION: This method of manufacturing the rotation-linear motion converting mechanism 1 comprises steps as follows. The step of assembling a first assembly by combining a magnetized sun shaft body 31 with planetary shaft bodies 41. The step of assembling a second assembly by combining the first assembly with a front ring gear 22. The step of assembling a third assembly by combining the second assembly with a ring shaft body 21. The step of assembling a gear assembly by combining gears 23, 33 and 43 with one another. The step of assembling a fourth assembly by combining the third assembly with the gear assembly. The step of assembling the rotation-linear motion converting mechanism 1 by combining the fourth assembly with collars 51, 52. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a rotational linear motion conversion mechanism that converts rotational motion into linear motion.

As a rotation linear motion conversion mechanism, for example, one described in Patent Document 1 is known.
This rotational linear motion conversion mechanism is configured by a combination of an annular shaft having a space extending in the axial direction therein, a solar shaft disposed inside the annular shaft, and a plurality of planetary shafts disposed around the solar shaft. Has been. Further, the female screw of the annular shaft, the male screw of the sun shaft, and the male screw of the planetary shaft are engaged with each other. In the rotational linear motion conversion mechanism having such a structure, when the annular shaft is rotated, the solar shaft linearly moves by the planetary shaft moving around the solar axis through the force transmitted from the annular shaft. It becomes like this. That is, it is possible to convert the rotational motion of the annular shaft into the linear motion of the solar shaft.
JP-A-10-196757

  By the way, in the manufacturing process of the rotating linear motion conversion mechanism, the planetary axis is between the annular axis and the sun axis relative to the reference attitude (the attitude where the center line of the planet axis is parallel to the center line of the sun axis). It has been confirmed by the present inventor that this state is inclined. The reason why the planetary axis is tilted in this way is considered as follows.

  In the rotational linear motion conversion mechanism, the number of threads of each component is set to a different value. Therefore, when the female screw of the annular shaft and the male screw of the sun shaft are engaged with the male screw of each planetary shaft, these screws are used. A backlash is formed between the two. Moreover, the magnitude | size of this backlash changes according to the setting aspect of the number of strips of each screw. Therefore, in the manufacturing process of the rotating linear motion conversion mechanism, when a force is applied to the planetary axis in accordance with the combination of each component, the planetary axis is tilted by moving the planetary axis in the direction of the backlash. The rotating linear motion conversion mechanism may be assembled.

  For example, when the annular shaft is assembled to an assembly in which the sun axis and the planetary axis are combined in the production of the rotational linear motion conversion mechanism, the annular axis is used when the female screw of the annular axis is engaged with the male screw of the planetary axis. Since a force is applied to the planetary axis from, the inclination of the planetary axis occurs as described above.

  When the planetary shaft is tilted with respect to the reference posture in the rotational linear motion conversion mechanism, the screw engagement of each component will be non-uniform, so that the wear of the screws will be promoted locally, leading to a reduction in the service life. become. In addition, since the friction between the constituent elements increases, the conversion efficiency from the rotational motion to the linear motion is reduced.

  Therefore, in order to suppress the inclination of the planetary axis due to the production of the rotational linear motion conversion mechanism as described above, for example, a retainer is attached to both ends of the planetary axis for an assembly in which the sun axis and the planetary axis are combined. It is also possible to constrain the attitude of the planetary axis by Incidentally, since Patent Document 1 discloses a rotational linear motion conversion mechanism having a structure having a retainer, it is considered that the attitude of the planetary shaft is constrained by the retainer during the manufacture thereof.

  However, in such a manufacturing method, it is difficult to say that the inclination of the planetary shaft is sufficiently suppressed because the phase of each retainer may shift as the annular shaft is screwed into the aggregate. Therefore, it is conceivable to connect two retainers to each other through a plurality of shafts in order to suppress a phase shift. In this case, an axis connecting the retainers is arranged between the planetary shafts. Depending on the structure of the motion conversion mechanism, the required number of shafts may not be attached to each retainer. That is, it becomes difficult to sufficiently suppress the inclination of the planetary axis.

  The present invention has been made in view of such circumstances, and the object thereof is a rotational linear motion conversion mechanism capable of suppressing the inclination of the planetary shaft in response to more various structures of the rotational linear motion conversion mechanism. It is in providing the manufacturing method of.

In the following, means for achieving the above object and its effects are described.
(1) The invention according to claim 1 is an annular shaft having a space extending in the axial direction therein, a solar shaft disposed inside the annular shaft, and a plurality of planets disposed around the solar shaft. A shaft, the annular shaft is configured to include an annular shaft body having a female thread, the sun shaft is configured to include a solar shaft body having a male thread, and the planetary shaft is A planetary shaft main body having a male screw, a female screw of the annular shaft main body meshing with a male screw of the planetary shaft main body, a male screw of the solar shaft main body and a male screw of the planetary shaft main body meshing And a rotational linear motion configured such that the other of the annular shaft and the sun shaft moves linearly through the planetary motion of the planetary shaft accompanying the rotational motion of one of the annular shaft and the sun shaft. Regarding the conversion mechanism, the following The manufacturing process including the second step and the third step is performed as follows. “First step of magnetizing the solar shaft body”, “The center line of the planetary shaft body is parallel to the center line of the solar shaft body. The attitude of the planetary shaft main body is a reference attitude, and an aggregate configured by a combination of the sun axis main body and the planetary axis main body is defined as a first aggregate. “Second step of assembling the first assembly in a state of being held in a reference posture”, “an assembly composed of a combination of the first assembly and the annular shaft body as a second assembly, The gist is “a third step of assembling the second aggregate in a state where the main body is magnetized”.

  (2) The invention according to claim 2 is an annular shaft having a space extending in the axial direction therein, a solar shaft disposed inside the annular shaft, and a plurality of planets disposed around the solar shaft. A shaft, the annular shaft is configured to include an annular shaft body having a female thread, the sun shaft is configured to include a solar shaft body having a male thread, and the planetary shaft is A planetary shaft main body having a male screw, a female screw of the annular shaft main body and a male screw of the planetary shaft main body mesh with each other, a male screw of the sun shaft main body and a male screw of the planetary shaft main body mesh with each other And a rotational linear motion configured such that the other of the annular shaft and the sun shaft moves linearly through the planetary motion of the planetary shaft accompanying the rotational motion of one of the annular shaft and the sun shaft. Regarding the conversion mechanism, the following The second step and the third step are performed to manufacture the product. “The orientation of the planetary shaft body in which the centerline of the planetary shaft body is parallel to the centerline of the solar shaft body is a reference posture, “A first step of assembling the first aggregate in a state in which the planetary shaft main body is held in the reference posture, with an aggregate constituted by a combination of the sun axis main body and the planetary axis main body as a first aggregate”, “ “Second step of magnetizing the solar axis main body of the first aggregate”, “an aggregate constituted by a combination of the first aggregate and the annular shaft main body as a second aggregate, and the solar axis main body The gist of the present invention is “a third step of assembling the second assembly in a state where is magnetized”.

  In the first and second aspects of the invention, the second aggregate is assembled in a state where each planetary shaft main body is fixed to the solar shaft main body by the magnetization of the solar shaft main body. Thereby, since each planetary shaft main body is held in a fixed posture (reference posture) when the annular shaft main body is assembled to the first aggregate, the rotation linear motion conversion mechanism is assembled with the planetary shaft tilted. Can be suppressed. In addition, since the attitude of the planetary shaft main body is constrained through the magnetization of the solar shaft main body, unlike the manufacturing method using the retainer described above, regardless of the number of planetary shafts arranged in the rotational linear motion conversion mechanism. It becomes possible to suppress the inclination of the planetary axis. As described above, according to the manufacturing method of the present invention, it becomes possible to suppress the inclination of the planetary shaft corresponding to the various structures of the rotary linear motion conversion mechanism.

  (3) The invention according to claim 3 is the method of manufacturing the rotational linear motion conversion mechanism according to claim 1 or 2, wherein the annular shaft includes the annular shaft main body and an internal annular gear. The sun shaft is configured to include the sun shaft main body and the external toothed gear, and the planetary shaft includes the planetary shaft body and the outer planetary gear. As the annular gear, a first annular gear provided at one end of the annular shaft main body and a second annular gear provided at the other end of the annular shaft main body are configured. Providing, as the sun gear, a first sun gear provided at one end of the sun shaft main body and a second sun gear provided at the other end of the sun shaft main body, as the planetary gear A first planetary gear provided at one end of the planetary shaft body and the planetary shaft body A second planetary gear provided at the other end, the first annular gear is formed separately from the annular shaft main body, and the second sun gear is different from the solar shaft main body. Being formed separately, the second planetary gear being formed separately from the planetary shaft body, the first annular gear and the first planetary gear meshing, the second annular gear and the The rotational linear motion configured such that the second planetary gear meshes, the first sun gear and the first planetary gear mesh, and the second sun gear and the second planetary gear mesh. The conversion mechanism is manufactured including the following fourth step. “The assembly composed of a combination of the second assembly and the second planetary gear is used as a third assembly, and the solar shaft body is magnetized. Assemble the third assembly Are summarized as fourth step "it.

  In the manufacturing process of the rotating linear motion conversion mechanism, if the planetary shaft body of the second aggregate is excessively inclined with respect to the reference posture, the second planetary gear cannot be assembled to the planetary shaft body. When such a situation occurs, the assembly work is temporarily interrupted, leading to a decrease in productivity. In this regard, in the above invention, since the planetary shaft body is held in the reference posture by being attracted to the sunshaft body, the combination of the second aggregate and the second planetary gear is performed. It comes to be assembled to the second assembly accurately. Thereby, it becomes possible to suppress a reduction in productivity.

  (4) The invention described in claim 4 is the method for manufacturing the rotational linear motion conversion mechanism according to claim 1 or 2, wherein the rotational linear motion conversion mechanism is manufactured including the following fifth step. The gist is “fifth step of demagnetizing the solar shaft main body after the third step”.

  In the above invention, since the rotating linear motion converting mechanism is assembled by demagnetizing the sun shaft main body, the rotating linear motion converting mechanism malfunctions due to foreign matter adsorbed on the sun shaft main body. This can be suppressed.

  (5) According to a fifth aspect of the present invention, in the manufacturing method of the rotational linear motion conversion mechanism according to the third aspect, the rotational linear motion conversion mechanism is manufactured including the following sixth step. The third annular gear, the first sun gear, and the first planetary gear are engaged with each other, and the second annular gear, the second sun gear, and the second planetary gear are engaged with each other. The gist of the assembly is “sixth step of demagnetizing the solar shaft body”.

  In the manufacturing process of the rotational linear motion conversion mechanism, the following problem arises when the sun shaft main body is demagnetized before the gear meshing state is obtained. That is, since the planetary shaft body is not attracted to the solar shaft body in a state where the end of the planetary shaft body is not constrained through the meshing of the gears, the planetary shaft body moves in the direction of the backlash of the screw to move the planetary shaft body. Tilt may occur. In this regard, in the above invention, the planetary shaft main body is demagnetized after the attitude of the planetary shaft main body is constrained through meshing with each planetary gear, each annular gear, and each sun gear. The inclination can be suitably suppressed.

  (6) The invention according to claim 6 is an annular shaft having a space extending in the axial direction therein, a solar shaft disposed inside the annular shaft, and a plurality of planets disposed around the solar shaft. A shaft, the annular shaft is configured to include an annular shaft body having a female thread, the sun shaft is configured to include a solar shaft body having a male thread, and the planetary shaft is A planetary shaft main body having a male screw, a female screw of the annular shaft main body and a male screw of the planetary shaft main body mesh with each other, a male screw of the sun shaft main body and a male screw of the planetary shaft main body mesh with each other And a rotational linear motion configured such that the other of the annular shaft and the sun shaft moves linearly through the planetary motion of the planetary shaft accompanying the rotational motion of one of the annular shaft and the sun shaft. Regarding the conversion mechanism, the following The manufacturing process including the second step and the third step is performed as follows. “First step of magnetizing the annular shaft main body”, “The center line of the planetary shaft main body is relative to the center line of the annular shaft main body. The planetary shaft main body after passing through the first step is defined as a first aggregate that is a combination of the annular shaft main body and the planetary shaft main body with the attitude of the planetary shaft main body being parallel as a reference posture. The second step of assembling the first assembly in a state where the main body is held in the reference posture "," an assembly composed of a combination of the first assembly and the solar shaft body as a second assembly, The gist is “a third step of assembling the second assembly in a state in which the annular shaft main body is magnetized”.

  (7) The invention according to claim 7 is an annular shaft having a space extending in the axial direction therein, a solar shaft disposed inside the annular shaft, and a plurality of planets disposed around the solar shaft. A shaft, the annular shaft is configured to include an annular shaft body having a female thread, the sun shaft is configured to include a solar shaft body having a male thread, and the planetary shaft is A planetary shaft main body having a male screw, a female screw of the annular shaft main body and a male screw of the planetary shaft main body mesh with each other, a male screw of the sun shaft main body and a male screw of the planetary shaft main body mesh with each other And a rotational linear motion configured such that the other of the annular shaft and the sun shaft moves linearly through the planetary motion of the planetary shaft accompanying the rotational motion of one of the annular shaft and the sun shaft. Regarding the conversion mechanism, the following The manufacturing process including the second step and the third step is performed as follows. “The center axis of the planetary shaft main body is parallel to the center line of the annular shaft main body as a reference posture, A first step of assembling the first aggregate in a state in which the planetary shaft main body is held in the reference posture, with the aggregate configured by a combination of the annular shaft main body and the planetary shaft main body as a first aggregate. , “A second step of magnetizing the annular shaft main body of the first assembly”, “an assembly formed by a combination of the first assembly and the solar shaft main body as a second assembly, The gist is “a third step of assembling the second assembly in a state in which the annular shaft main body is magnetized”.

  In the inventions according to claims 6 and 7, the second aggregate is assembled in a state where each planetary shaft body is fixed to the annular shaft body by the magnetization of the annular shaft body. As a result, each planetary shaft main body is held in a fixed posture (reference posture) when the solar shaft main body is assembled to the first assembly, and thus the rotation linear motion conversion mechanism is assembled with the planetary shaft tilted. It becomes possible to suppress. In addition, since the attitude of the planetary shaft body is constrained through the magnetization of the annular shaft body, unlike the manufacturing method using the retainer described above, it depends on the number of planetary axes arranged in the rotating linear motion conversion mechanism. It is possible to suppress the inclination of the planetary axis. As described above, according to the manufacturing method of the present invention, it becomes possible to suppress the inclination of the planetary shaft corresponding to the various structures of the rotary linear motion conversion mechanism.

  (8) The invention according to claim 8 is the method of manufacturing a rotational linear motion conversion mechanism according to claim 6 or 7, wherein the annular shaft includes the annular shaft main body and an internal annular gear. The sun shaft is configured to include the sun shaft main body and the external toothed gear, and the planetary shaft includes the planetary shaft body and the outer planetary gear. As the annular gear, a first annular gear provided at one end of the annular shaft main body and a second annular gear provided at the other end of the annular shaft main body are configured. Providing, as the sun gear, a first sun gear provided at one end of the sun shaft main body and a second sun gear provided at the other end of the sun shaft main body, as the planetary gear A first planetary gear provided at one end of the planetary shaft body and the planetary shaft body A second planetary gear provided at the other end, the first annular gear is formed separately from the annular shaft main body, and the second sun gear is different from the solar shaft main body. Being formed separately, the second planetary gear being formed separately from the planetary shaft body, the first annular gear and the first planetary gear meshing, the second annular gear and the The rotational linear motion configured such that the second planetary gear meshes, the first sun gear and the first planetary gear mesh, and the second sun gear and the second planetary gear mesh. About the conversion mechanism, the manufacturing is performed including the following fourth step. “The assembly formed by the combination of the second assembly and the second planetary gear is defined as a third assembly, and the annular shaft body is Assembling the third assembly in a magnetized state Are summarized as fourth step "it.

  In the manufacturing process of the rotating linear motion conversion mechanism, if the planetary shaft body of the second aggregate is excessively inclined with respect to the reference posture, the second planetary gear cannot be assembled to the planetary shaft body. When such a situation occurs, the assembly work is temporarily interrupted, leading to a decrease in productivity. In this regard, in the above-described invention, the second planetary gear is combined with the second aggregated gear and the second planetary gear while the planetary shaft main body is held in the reference posture by being attracted to the annular shaft main body. Can be accurately assembled to the second assembly. Thereby, it becomes possible to suppress a reduction in productivity.

  (9) The invention according to claim 9 is the method of manufacturing the rotational linear motion conversion mechanism according to claim 6 or 7, wherein the rotational linear motion conversion mechanism is manufactured including the following fifth step. The gist is “fifth step of demagnetizing the annular shaft main body after the third step”.

  In the above invention, since the rotating shaft motion conversion mechanism is assembled by demagnetizing the ring shaft main body, the rotation linear motion conversion mechanism malfunctions due to foreign matter being adsorbed on the ring shaft main body. Can be suppressed.

  (10) The invention according to claim 10 is the manufacturing method of the rotating linear motion converting mechanism according to claim 8, wherein the rotating linear motion converting mechanism is manufactured including the following sixth step. The third annular gear, the first sun gear, and the first planetary gear are engaged with each other, and the second annular gear, the second sun gear, and the second planetary gear are engaged with each other. The gist of the assembly is “sixth step of demagnetizing the annular shaft body”.

  In the manufacturing process of the rotary linear motion conversion mechanism, the following problem arises when the annular shaft body is demagnetized before the meshing state of the gear is obtained. That is, the planetary shaft main body is not attracted to the annular shaft main body in a state where the end of the planetary shaft main body is not restrained through the meshing of the gears. There may be a tilt of In this regard, in the above invention, the planetary shaft main body is demagnetized after the attitude of the planetary shaft main body is constrained through the meshing of each planetary gear with each annular gear and each sun gear. It is possible to suitably suppress the inclination of.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates according to the order of the structure of the rotation linear motion conversion mechanism assembled through the manufacturing method of this embodiment, the operation | movement aspect of the conversion mechanism, and the manufacturing method of a rotation linear motion conversion mechanism.

<Structure of rotating linear motion conversion mechanism>
With reference to FIG.1 and FIG.2, the outline of the structure of the rotation linear motion conversion mechanism 1 is demonstrated.
FIG. 1 shows a perspective structure of the rotating linear motion conversion mechanism 1.
FIG. 2 shows a perspective structure inside the rotary linear motion conversion mechanism 1.

  The rotary linear motion conversion mechanism 1 includes a ring shaft 2 having a space extending in the axial direction therein, a sun shaft 3 disposed inside the ring shaft 2, and a plurality of planetary shafts 4 disposed around the sun shaft 3. It is comprised by the combination. The ring shaft 2 and the sun shaft 3 are arranged in a state in which the respective center lines are aligned or substantially aligned with each other. The sun shaft 3 and each planetary shaft 4 are arranged in a state where their center lines are parallel to each other or substantially parallel to each other. The planetary shafts 4 are arranged at equal intervals around the sun shaft 3.

  In the present embodiment, for each component of the rotational linear motion conversion mechanism 1, the posture in which the center line of the rotating linear motion conversion mechanism 1 is aligned with the center line of the sun shaft 3 and the posture in which the center line is substantially aligned are defined as the alignment posture. In addition, a posture in which the center line of itself is parallel to and substantially parallel to the center line of the sun shaft 3 is defined as a parallel posture. That is, the ring shaft 2 constitutes the rotary linear motion conversion mechanism 1 in a state where the ring shaft 2 is held in the aligned posture. Each planetary shaft 4 constitutes the rotational linear motion conversion mechanism 1 in a state where it is held in a parallel posture.

  In the rotational linear motion conversion mechanism 1, one of the components of the ring shaft 2 and each planetary shaft 4 is engaged by meshing between the screws and gears provided on the ring shaft 2 and the screws and gears provided on each planetary shaft 4. Force is transmitted to the other component. Further, due to the engagement of the screw and gear provided on the sun shaft 3 and the screw and gear provided on each planetary shaft 4, a force is applied from one component of the sun shaft 3 and each planetary shaft 4 to the other component. Communicated.

  The rotating linear motion conversion mechanism 1 operates as follows based on the combination of these components. That is, when one component of the ring shaft 2 and the sun shaft 3 rotates, each planetary shaft 4 performs a planetary motion around the sun shaft 3 through the force transmitted from the component. Thereby, the component moves in the axial direction with respect to each planetary shaft 4 through the force transmitted from each planetary shaft 4 to the other component of the ring shaft 2 and the sun shaft 3.

  As described above, the rotational linear motion conversion mechanism 1 converts the rotational motion of one of the ring shaft 2 and the sun shaft 3 into the other linear motion of the ring shaft 2 and the sun shaft 3. In the present embodiment, with respect to the axial direction of the sun shaft 3, the direction in which the sun shaft 3 is pushed out from the ring shaft 2 is the front direction FR, and the direction in which the sun shaft 3 is pulled into the ring shaft 2 is the back direction RR. Yes. Further, when an arbitrary position of the rotational linear motion conversion mechanism 1 is used as a reference, a range on the front direction FR side from the reference position is a front side, and a range on the back direction RR side from the reference position is a back side. Yes.

  A front collar 51 and a rear collar 52 that support the sun shaft 3 are fixed to the ring shaft 2. That is, the ring shaft 2, the front collar 51, and the rear collar 52 move integrally. In the ring shaft 2, the opening on the front side is closed by the front collar 51. Further, the opening on the back side is closed by the back collar 52.

  The sun shaft 3 is supported by a bearing 51A of the front collar 51 and a bearing 52A of the rear collar 52. On the other hand, each planetary shaft 4 is not supported by either the front collar 51 or the rear collar 52. That is, in the rotational linear motion conversion mechanism 1, the radial position of the sun shaft 3 is restrained by the engagement of the screw and gear and the front collar 51 and the rear collar 52, while the radial direction of each planetary shaft 4 is The position is constrained only by the engagement of the screw and gear.

  The rotating linear motion conversion mechanism 1 employs the following structure to lubricate the inside of the ring shaft 2 (where the screws and gears of the ring shaft 2, the sun shaft 3 and each planetary shaft 4 are engaged). Has been. That is, a plurality of oil holes 51 </ b> H for supplying lubricating oil to the inside of the ring shaft 2 are formed in the front collar 51. An O-ring 53 that seals the inside of the ring shaft 2 is attached to each of the front collar 51 and the rear collar 52.

[1] “Ring shaft structure”
The structure of the ring shaft 2 will be described with reference to FIG.
FIG. 3A shows a cross-sectional structure of the ring shaft 2.
FIG. 3B shows a cross-sectional structure in which a part of the ring shaft 2 is disassembled.

  The ring shaft 2 is configured by a combination of a ring shaft main body 21 (annular shaft main body), a front ring gear 22 and a rear ring gear 23. In the ring shaft 2, the center line (axis line) of the ring shaft main body 21 corresponds to the center line (axis line) of the ring shaft 2. Therefore, the alignment posture of the ring shaft 2 is ensured when the center line of the ring shaft main body 21 is aligned or substantially aligned with the center line of the sun shaft 3.

  The ring shaft main body 21 includes a main body screw portion 21A having an internal thread 24 formed on the inner peripheral surface, a main body gear portion 21B to which the front ring gear 22 is assembled, and a main body gear portion 21C to which the rear ring gear 23 is assembled. It is configured.

  The front ring gear 22 is formed separately from the ring shaft main body 21 as a flat-toothed internal gear. Further, when assembled to the ring shaft main body 21, its own center line is configured to match the center line of the ring shaft main body 21. In the present embodiment, the front ring gear 22 is fixed to the ring shaft main body 21 by press-fitting as to how the front ring gear 22 is assembled to the ring shaft main body 21. The front ring gear 22 can be fixed to the ring shaft main body 21 by a method other than press fitting.

  The back ring gear 23 is formed separately from the ring shaft main body 21 as a flat-toothed internal gear. Further, when assembled to the ring shaft main body 21, its own center line is configured to match the center line of the ring shaft main body 21. In the present embodiment, the back ring gear 23 is fixed to the ring shaft main body 21 by press-fitting as to how the back ring gear 23 is assembled to the ring shaft main body 21. The back ring gear 23 can be fixed to the ring shaft main body 21 by a method other than press fitting.

  In the ring shaft 2, the front ring gear 22 and the rear ring gear 23 are configured as gears having the same shape. That is, the specifications (reference pitch circle diameter, number of teeth, etc.) of the front ring gear 22 and the rear ring gear 23 are set to be equal to each other.

[2] "Sunshaft structure"
The structure of the sun shaft 3 will be described with reference to FIG.
FIG. 4A shows the front structure of the sun shaft 3.
FIG. 4B shows a front structure in a state where a part of the sunshaft 3 is disassembled.

  The sun shaft 3 is configured by a combination of a sun shaft main body 31 (sun shaft main body) and a rear sun gear 33. In the sun shaft 3, the center line (axis line) of the sun shaft main body 31 corresponds to the center line (axis line) of the sun shaft 3.

  The sunshaft main body 31 includes a main body screw portion 31A having a male thread 34 formed on the outer peripheral surface, a main body gear portion 31B having a spur toothed external gear (front sun gear 32), and a main body gear portion to which the rear sun gear 33 is assembled. And 31C. Further, it is made of a ferromagnetic material.

  The rear sun gear 33 is formed as a spur external gear separately from the sun shaft main body 31. Further, when assembled to the sun shaft main body 31, the center line of the sun shaft main body 31 is aligned with the center line of the sun shaft main body 31. In the present embodiment, the back sun gear 33 is fixed to the sun shaft main body 31 by press-fitting as to how the back sun gear 33 is assembled to the sun shaft main body 31. The back sun gear 33 can be fixed to the sun shaft main body 31 by a method other than press fitting.

  In the sun shaft 3, the front sun gear 32 and the rear sun gear 33 are configured as gears having the same shape. That is, the specifications (reference pitch circle diameter, number of teeth, etc.) of the front sun gear 32 and the back sun gear 33 are set to be equal to each other.

[3] “Planetary shaft structure”
The structure of the planetary shaft 4 will be described with reference to FIG.
FIG. 5A shows the front structure of the planetary shaft 4.
FIG. 5B shows a front structure in a state where a part of the planetary shaft 4 is disassembled.
FIG. 5C shows a cross-sectional structure of the back planetary gear 43 along the center line.

  The planetary shaft 4 is configured by a combination of a planetary shaft main body 41 (planetary axis main body) and a back planetary gear 43. In the planetary shaft 4, the center line (axis line) of the planetary shaft body 41 corresponds to the center line (axis line) of the planetary shaft 4. Accordingly, when the center line of the planetary shaft main body 41 is parallel or substantially parallel to the center line of the sun shaft 3, the parallel posture of the planetary shaft 4 is ensured.

  The planetary shaft main body 41 has a rear surface to which a main body screw portion 41A having a male screw 44 formed on the outer peripheral surface, a main body gear portion 41B having a spur external gear (front planetary gear 42) and a rear planetary gear 43 are assembled. The side shaft 41 </ b> R and the front side shaft 41 </ b> F fitted into a jig when the rotary linear motion conversion mechanism 1 is assembled are configured. Further, it is made of a ferromagnetic material.

  The back planetary gear 43 is formed separately from the planetary shaft main body 41 as a spur external gear. Further, the rear shaft 41R of the planetary shaft main body 41 is assembled into the planetary shaft main body 41 by being inserted into the bearing hole 43H. Further, in the state where it is assembled to the planetary shaft main body 41, its own center line is configured to be aligned with the center line of the planetary shaft main body 41.

  As for the manner of assembling the back planetary gear 43 with respect to the planetary shaft main body 41, in this embodiment, a clearance fit is adopted so that the back planetary gear 43 can rotate relative to the planetary shaft main body 41. In addition, as an assembling mode for obtaining relative rotation between the planetary shaft main body 41 and the back planetary gear 43, an assembling mode other than clearance fitting can be adopted.

  In the planetary shaft 4, the front planetary gear 42 and the rear planetary gear 43 are configured as gears having the same shape. That is, the specifications (reference pitch circle diameter, the number of teeth, etc.) of the front planetary gear 42 and the back planetary gear 43 are set to be equal to each other.

[4] “Relationship between components”
With reference to FIGS. 6-9, the relationship of each component in the rotation linear motion conversion mechanism 1 is demonstrated. In addition, although the rotation linear motion conversion mechanism 1 of the structure provided with the nine planetary shafts 4 is illustrated here, the number of arrangement | positioning of the planetary shafts 4 can be changed suitably.
FIG. 6 shows a cross-sectional structure of the rotational linear motion conversion mechanism 1 along the center line of the sun shaft 3.
FIG. 7 shows a cross-sectional structure of the rotational linear motion conversion mechanism 1 along the DA-DA line of FIG.
FIG. 8 shows a cross-sectional structure of the rotational linear motion conversion mechanism 1 along the DB-DB line of FIG.
FIG. 9 shows a cross-sectional structure of the rotational linear motion conversion mechanism 1 along the DC-DC line of FIG.

In the rotating linear motion conversion mechanism 1, the operation of each component is allowed or restricted as follows.
(A) About the ring shaft 2, relative rotation with the ring shaft main body 21, the front ring gear 22, and the back ring gear 23 is made impossible. Further, relative rotation between the ring shaft main body 21 and the front collar 51 and the rear collar 52 is disabled.
(B) About the sun shaft 3, relative rotation between the sun shaft main body 31 and the back sun gear 33 is disabled.
(C) About the planetary shaft 4, relative rotation between the planetary shaft main body 41 and the back planetary gear 43 is allowed.

  In the rotary linear motion conversion mechanism 1, the force is transmitted between these components through the engagement of screws and gears of the ring shaft 2, the sun shaft 3, and the planetary shafts 4 as follows.

  In the ring shaft 2 and each planetary shaft 4, the female screw 24 of the ring shaft main body 21 and the male screw 44 of each planetary shaft main body 41 are engaged with each other. Further, the front ring gear 22 of the ring shaft main body 21 and the front planetary gear 42 of each planetary shaft main body 41 are engaged with each other. Further, the rear ring gear 23 of the ring shaft main body 21 and the rear planetary gear 43 of each planetary shaft main body 41 are engaged with each other.

  Thus, when a rotational motion is input to one of the ring shaft 2 and each planetary shaft 4, the engagement of the female screw 24 and the male screw 44, the engagement of the front ring gear 22 and the front planetary gear 42, and the rear ring gear 23, A force is transmitted to the other of the ring shaft 2 and each planetary shaft 4 through meshing with the rear planetary gear 43.

  In the sun shaft 3 and each planetary shaft 4, the male screw 34 of the sun shaft main body 31 and the male screw 44 of each planetary shaft main body 41 are engaged with each other. Further, the front sun gear 32 of the sun shaft main body 31 and the front planetary gear 42 of each planetary shaft main body 41 are engaged with each other. Further, the rear sun gear 33 of the sun shaft main body 31 and the rear planetary gear 43 of each planetary shaft main body 41 are engaged with each other.

  Thus, when a rotational motion is input to one of the sun shaft 3 and each planetary shaft 4, the male screw 34 and the male screw 44 are engaged, the front sun gear 32 and the front planetary gear 42 are engaged, and the rear sun gear 33 and the rear planetary gear are engaged. Through engagement with the gear 43, force is transmitted to the other of the sun shaft 3 and each planetary shaft 4.

  As described above, the rotational linear motion conversion mechanism 1 includes the speed reduction mechanism constituted by the female screw 24 of the ring shaft 2, the male screw 34 of the sun shaft 3, and the male screw 44 of each planetary shaft 4, the front ring gear 22 and the front sun gear 32. A speed reduction mechanism constituted by each front planetary gear 42 and a speed reduction mechanism constituted by the rear ring gear 23, the rear sun gear 33, and each rear planetary gear 43 are configured.

<Operation Mode of Rotating Linear Motion Conversion Mechanism>
In the rotational linear motion conversion mechanism 1, an operation method (motion conversion method) for converting rotational motion into linear motion is determined based on the setting mode of the number of teeth of each gear and the number of threads of each screw. That is, as a motion conversion method, either a sun axis displacement method in which the sun shaft 3 is linearly moved by the rotational motion of the ring shaft 2 or an annular shaft displacement method in which the ring shaft 2 is linearly moved by the rotational motion of the sun shaft 3 is selected. Can be selected. Hereinafter, the operation | movement aspect of the rotation linear motion conversion mechanism 1 in each motion conversion system is demonstrated.

  (A) When the solar axis displacement method is adopted as the motion conversion method, conversion from rotational motion to linear motion is performed as follows. That is, when rotational motion is input to the ring shaft 2, the front ring gear 22 and each front planetary gear 42 are engaged, the rear ring gear 23 and each rear planetary gear 43 are engaged, and the female screw 24 and each male screw 44 are engaged. By transmitting force from the ring shaft 2 to each planetary shaft 4 through the meshing, each planetary shaft 4 revolves around the sun shaft 3 while rotating. In accordance with the planetary movement of the planetary shaft 4, each front planetary gear 42 and the front sun gear 32 are engaged with each other, each rear planetary gear 43 and the rear sun gear 33 are engaged, and each male screw 44 and the male screw 34 are engaged. When the force is transmitted from the planetary shaft 4 to the sun shaft 3, the sun shaft 3 is displaced in the axial direction.

  (B) In the case where the annular shaft displacement method is adopted as the motion conversion method, conversion from rotational motion to linear motion is performed as follows. That is, when rotational motion is input to the sunshaft 3, the front sun gear 32 and the front planetary gear 42 are engaged, the rear sun gear 33 and the rear planetary gear 43 are engaged, and the male screw 34 and the male screw 44 are engaged. By transmitting force from the sun shaft 3 to each planetary shaft 4, each planetary shaft 4 revolves while rotating around the sun shaft 3. In accordance with the planetary movement of the planetary shaft 4, the front planetary gears 42 and the front ring gear 22 are engaged, the rear planetary gears 43 and the rear ring gear 23 are engaged, and the male screws 44 and the female screws 24 are engaged. When the force is transmitted from each planetary shaft 4 to the ring shaft 2 through the ring shaft 2, the ring shaft 2 is displaced in the axial direction.

<Method for manufacturing rotational linear motion conversion mechanism>
With reference to FIGS. 10-20, the manufacturing method of a rotation linear motion conversion mechanism is demonstrated. In the manufacturing method of the present embodiment, the rotation linear motion conversion mechanism 1 is manufactured including the following processes A to J. In addition, the rotation linear motion conversion mechanism 1 provided with the nine planetary shafts 4 is assumed here.

  [Step A (FIG. 10)] The ring shaft main body 21, the sun shaft main body 31, the planetary shaft main body 41, the front ring gear 22, the rear ring gear 23, the rear sun gear 33, and the rear planetary gear 43 are cleaned.

[Step B (FIG. 11)] The sun shaft main body 31 is magnetized by the magnetizing device 71.
[Step C (FIG. 12)] The sunshaft body 31 is attached to the basic jig 61.
The structure of the basic jig 61 will be described with reference to FIG.
FIG. 13A shows the front structure of the basic jig 61.
FIG. 13B shows a cross-sectional structure of the basic jig 61 along the DD-DD line.

  The basic jig 61 includes a sun jig 62 for fixing the sunshaft main body 31 and a planetary jig 63 for supporting the front side shaft 41F of the planetary shaft main body 41. That is, the same number of planetary jigs 63 as the number of planetary shafts 4 provided in the rotary linear motion conversion mechanism 1 are formed integrally with the sun jig 62.

  The sun jig 62 is configured such that its center line (center line of the insertion hole 62H) is aligned with the center line of the sun shaft body 31 in a state where the sun shaft body 31 is inserted into the insertion hole 62H. Each planetary jig 63 is configured such that the center lines thereof are equally spaced around the center line of the insertion hole 62H. The sun jig 62 and each planetary jig 63 are configured such that their center lines are parallel to each other. A support hole 63H corresponding to the shape of the front shaft 41F of the planetary shaft main body 41 is formed at the tip of each planetary jig 63.

  When each front shaft 41F is fitted into the support hole 63H in a state where the center line of the planetary shaft main body 41 and the center line of the planetary jig 63 are aligned, the planetary shaft main body 41 surrounds the sun shaft main body 31 in a parallel posture. Are arranged at equal intervals.

In step C, specifically, the sunshaft body 31 is attached to the basic jig 61 through the following operations (a) and (b).
(A): A portion of the sun shaft main body 31 that is located on the front side of the front sun gear 32 is inserted into the sun jig 62.
(B): The sunshaft body 31 is fixed to the sun jig 62.

[Step D (FIG. 14)] An assembly (first assembly 91 (first assembly)) constituted by a combination of the sun shaft main body 31 and each planetary shaft main body 41 is assembled. That is, the first assembly 91 is assembled by assembling each planetary shaft body 41 to the sun shaft body 31. Specifically, the following operations (a) and (b) are performed as operations for assembling the first assembly 91 and operations associated therewith.
(A): Each planetary shaft so that the center line of the planetary shaft main body 41 is aligned with the center line of the planetary jig 63, that is, the planetary shaft main body 41 is attracted to the sun shaft main body 31 in a parallel posture. The front shaft 41 </ b> F of the main body 41 is attached to the planetary jig 63.
(B): The male screw 34 of the sun shaft main body 31 and the male screw 44 of each planetary shaft main body 41 are engaged with each other and the front sun gear 32 and each front planetary gear 42 are engaged in accordance with the operation (a).

[Step E (FIG. 15)] An assembly (second assembly 92) constituted by a combination of the first assembly 91 and the front ring gear 22 is assembled. That is, the second assembly 92 is assembled by assembling the front ring gear 22 to the first assembly 91. Specifically, the second assembly 92 is assembled through the following operations (a) and (b).
(A): The front ring gear 22 is arranged at a position where the center line of the sun shaft main body 31 and the center line of the sun shaft main body 31 are aligned on the back side of the first assembly 91.
(B): The front ring gear 22 and the front planetary gears 42 are engaged with each other.

[Step F (FIG. 16)] An assembly (third assembly 93 (second assembly)) constituted by a combination of the second assembly 92 and the ring shaft main body 21 is assembled. That is, the third assembly 93 is assembled by assembling the ring shaft main body 21 to the second assembly 92. Specifically, the third assembly 93 is assembled through the following operations (a) to (c).
(A): The ring shaft main body 21 is disposed at a position where the center line of the sun shaft main body 31 and the center line of the sun shaft main body 31 are aligned on the back side of the second assembly 92.
(B): The female screw 24 of the ring shaft main body 21 is engaged with the male screw 44 of each planetary shaft main body 41 and screwed to a predetermined position.
(C): The front ring gear 22 is fixed to the ring shaft main body 21 by press-fitting into the main body gear portion 21B.

[Step G (FIG. 17)] An assembly (gear assembly 99) constituted by a combination of the rear ring gear 23, the rear sun gear 33, and each rear planetary gear 43 is assembled. Specifically, the following operations (a) and (b) are performed as operations for assembling the gear assembly 99 and operations accompanying it.
(A): The rear ring gear 23, the rear sun gear 33, and the respective rear planetary gears 43 are attached to the corresponding positions of the gear jig 64. That is, on the gear jig 64, the rear ring gear 23 and the rear sun gear 33 are engaged with the respective rear planetary gears 43. Through this operation, the gear assembly 99 is in a state where the center line of the back ring gear 23 and the center line of the back sun gear 33 are aligned and the center line of each back planetary gear 43 is parallel to the center line of the back sun gear 33. Is assembled.
(B): After removing the gear assembly 99 from the gear jig 64, the gear assembly 99 is placed at a position where the center lines of the rear ring gear 23 and the rear sun gear 33 are aligned with the center line of the ring shaft body 21 of the third assembly 93. Moving. Through this operation, the back ring gear 23 and the back sun gear 33 are held in the aligned posture, and the back planetary gears 43 are held in the parallel posture.

[Step H (FIG. 18)] An assembly (fourth assembly 94 (third assembly)) constituted by a combination of the third assembly 93 and the gear assembly 99 is assembled. That is, the fourth assembly 94 is assembled by assembling the gear assembly 99 to the third assembly 93. Specifically, the fourth assembly 94 is assembled through the following operations (a) to (c).
(A): Each rear planetary gear 43 of the gear assembly 99 is attached to the corresponding rear shaft 41R of the planetary shaft main body 41.
(B): The rear ring gear 23 is fitted into the main body gear portion 21 </ b> C of the ring shaft main body 21 and then press-fitted into the ring shaft main body 21.
(C): The rear sun gear 33 is fitted into the main body gear portion 31 </ b> C of the sun shaft main body 31 and then press-fitted into the sun shaft main body 31.

[Step I (FIG. 19)] The sun shaft main body 31 of the fourth assembly 94 is demagnetized by the demagnetizer 72.
[Step J (FIG. 20)] An assembly (rotational linear motion conversion mechanism 1) constituted by a combination of the fourth assembly 94 and the front collar 51 and the rear collar 52 is assembled. That is, the rotary linear motion conversion mechanism 1 is assembled by assembling the front collar 51 and the rear collar 52 to the fourth assembly 94. Specifically, the rotary linear motion conversion mechanism 1 is assembled through the following operations (a) and (b).
(A): After attaching the O-ring 53 to the front collar 51, the front collar 51 is attached to the body gear portion 21B of the ring shaft body 21.
(B): After attaching the O-ring 53 to the back collar 52, the back collar 52 is attached to the body gear portion 21 </ b> C of the ring shaft body 21.

<Effect of embodiment>
As described above in detail, according to the method for manufacturing the rotational linear motion conversion mechanism according to the first embodiment, the following effects can be obtained.

  (1) In the rotational linear motion conversion mechanism 1, the number of threads of the ring shaft 2, the sun shaft 3 and each planetary shaft 4 is set to a different value, so that the female screw 24 of the ring shaft 2 and the male screw of the sun shaft 3 are set. Backlash is formed between the screws 34 and the male screws 44 of the planetary shafts 4 when they are engaged with each other. Moreover, the magnitude | size of this backlash changes according to the setting aspect of the number of strips of each screw. For this reason, when a force is applied to the planetary shaft main body 41 in accordance with the combination of each component in the manufacturing process of the rotary linear motion conversion mechanism 1, the planetary shaft main body 41 is moved in the direction in which the backlash is applied. The rotary linear motion conversion mechanism 1 may be assembled with the main body 41 tilted with respect to the parallel posture.

  For example, when the rotary linear motion conversion mechanism 1 is manufactured, when the ring shaft main body 21 is assembled to each planetary shaft main body 41 after combining the sun shaft main body 31 and each planetary shaft main body 41 as in this embodiment, In this way, the planetary shaft main body 41 is inclined. That is, when the female screw 24 of the ring shaft main body 21 is engaged with the male screw 44 of each planetary shaft main body 41, a force is applied from the ring shaft main body 21 to each planetary shaft main body 41, so that the planetary shaft main body 41 is subjected to the backlash. Therefore, the planetary shaft main body 41 is inclined.

  In this regard, in the manufacturing method of the present embodiment, the third assembly 93 is assembled in a state where each planetary shaft body 41 is fixed to the sunshaft body 31 through the magnetization of the sunshaft body 31. When assembled to the second assembly 92, each planetary shaft body 41 is held in a constant posture (parallel posture). As a result, it is possible to prevent the rotating linear motion conversion mechanism 1 from being assembled while the planetary shaft 4 is tilted.

  (2) In the manufacturing method of the present embodiment, the attitude of each planetary shaft body 41 is constrained through the magnetization of the sunshaft body 31, and therefore, unlike the manufacturing method using the retainer described above, rotational linear motion conversion is performed. Regardless of the number of planetary shafts 4 arranged in the mechanism 1, the inclination of each planetary shaft 4 can be suppressed. Thus, according to the manufacturing method of the present embodiment, it is possible to suppress the inclination of the planetary shaft 4 corresponding to more various structures of the rotary linear motion conversion mechanism 1.

  (3) In the rotating linear motion conversion mechanism 1, when the planetary shaft 4 is inclined with respect to the parallel posture, the meshing of the screws becomes uneven between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4. For this reason, the wear of the screw is locally promoted, resulting in a decrease in the service life. Further, since the friction between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4 is increased, the conversion efficiency from the rotational motion to the linear motion is also lowered.

  In this respect, according to the manufacturing method of the present embodiment, since the inclination of the planetary shaft body 41 accompanying the assembly of the rotary linear motion conversion mechanism 1 is suppressed, the life of the rotary linear motion conversion mechanism 1 is improved and the linear motion is linear. It becomes possible to improve the efficiency of conversion to exercise.

  (4) When the planetary shaft main body 41 of the third assembly 93 is excessively inclined with respect to the parallel posture in the manufacturing process of the rotary linear motion conversion mechanism 1, each rear planetary gear 43 of the gear assembly 99 is replaced with the planetary shaft main body 41. Cannot be assembled to the rear side shaft 41R. That is, the gear assembly 99 cannot be assembled to the third assembly 93. When such a situation occurs, the assembly work is temporarily interrupted, leading to a decrease in productivity.

  In this regard, according to the manufacturing method of the present embodiment, the third assembly 93 and the gear assembly 99 are combined with each planetary shaft body 41 held in a parallel posture through the magnetization of the sunshaft body 31. The gear assembly 99 can be accurately assembled to the third assembly 93. Thereby, it becomes possible to suppress a reduction in productivity.

  (5) In the manufacturing process of the rotating linear motion conversion mechanism 1, when the planetary shaft body 41 of the third assembly 93 is inclined with respect to the parallel posture but the degree of inclination is relatively small, each rear planetary of the gear assembly 99 is provided. The gear 43 can be assembled to the rear side shaft 41R of the planetary shaft main body 41. However, in this case, the following new problems arise. That is, since each back planetary gear 43 is assembled to the back side shaft 41R in a state of being inclined following the posture of the planetary shaft main body 41, the back ring gear 23 is in a state of being inclined with respect to the parallel posture. And the rear sun gear 33 is engaged. As a result, the meshing of the gears becomes uneven between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4, so that the wear of the gears is promoted locally, thereby reducing the life of the rotary linear motion conversion mechanism 1. To come to. Further, since the friction between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4 is increased, the conversion efficiency from the rotational motion to the linear motion is also lowered.

  In this regard, according to the manufacturing method of the present embodiment, the third assembly 93 and the gear assembly 99 are combined with each planetary shaft body 41 held in a parallel posture through the magnetization of the sunshaft body 31. Engagement with the back ring gear 23 and the back sun gear 33 in a state where each back planetary gear 43 is tilted is suppressed. As a result, the life of the rotary linear motion conversion mechanism 1 can be improved and the conversion efficiency from the rotary motion to the linear motion can be improved.

  (6) As a manufacturing method for suppressing the inclination of each planetary shaft main body 41 associated with the assembly of the ring shaft main body 21, in addition to the manufacturing method of the present embodiment, each planetary shaft main body 41 of the first assembly 91 or the second assembly 92 is provided. A manufacturing method in which both ends of the substrate are supported by a jig is conceivable. Here, as an example of such a jig, a retainer that collectively supports the front side shaft 41F of each planetary shaft main body 41, a retainer that collectively supports the rear side shaft 41R of each planetary shaft main body 41, and each of these retainers. Assume a jig composed of a plurality of shafts to be connected.

  According to the manufacturing method using this jig, the inclination of each planetary shaft main body 41 can be suppressed by assembling the ring shaft main body 21 to the second assembly 92 in a state where the jig is mounted. When the rear planetary gear 43 is assembled to the main body 41 (corresponding to the step of assembling the gear assembly 99 to the third assembly 93), it is necessary to remove the retainer mounted on the rear side shaft 41R from each planetary shaft main body 41. That is, the assembly (reference assembly (main assembly) in a state where the front ring gear 22 and the front sun gear 32 and the front planetary gear 42 are engaged with each other and the rear ring gear 23 and the rear sun gear 33 and the rear planetary gear 43 are engaged with each other. It is necessary to remove the retainer before assembling the fourth assembly 94 of the embodiment)).

  Thus, in the above manufacturing method, since the retainer is removed in a state where the rear planetary gear 43 of each planetary shaft main body 41 is not engaged with the corresponding gear, the inclination of the planetary shaft main body 41 when the rear planetary gear 43 is assembled. May occur. Incidentally, in the rotary linear motion conversion mechanism 1, the posture of the planetary shaft main body 41 may not be sufficiently restrained only by screw engagement due to backlash between the screws. At this time, the planetary shaft main body 41 is inclined by removing the retainer before assembling the reference assembly (fourth assembly 94 in the present embodiment). On the other hand, in the reference assembly, both ends of the planetary shaft main body 41 are constrained by the meshing of the respective gears, so that the inclination of the planetary shaft main body 41 is suppressed without restricting the attitude of the planetary shaft main body 41 through a jig or the like. It becomes like this.

  In contrast to the above manufacturing method, in the manufacturing method of the present embodiment, each planetary shaft main body 41 is restrained through the engagement of gears at both ends by restraining each planetary shaft main body 41 through magnetization of the sunshaft main body 31. The planetary shaft main bodies 41 can be held in a parallel posture. Therefore, the inclination of the planetary shaft main body 41 that occurs when the rear planetary gear 43 is assembled to each planetary shaft main body 41 can be suitably suppressed.

  (7) In the manufacturing method of the present embodiment, the sunshaft body 31 is demagnetized and the rotary linear motion conversion mechanism 1 is assembled. As a result, it is possible to suppress improper operation of the rotational linear motion conversion mechanism 1 due to the foreign matter being adsorbed on the sun shaft main body 31.

  (8) When the sunshaft body 31 is demagnetized before the reference assembly (the fourth assembly 94 in the present embodiment) is assembled in the manufacturing process of the rotating linear motion conversion mechanism 1, the following is performed. Is a problem. In this case, each planetary shaft main body 41 is not attracted to the sunshaft main body 31 in a state where both ends of each planetary shaft main body 41 are not constrained through the meshing of the gears. A tilt of 41 may occur.

  In this regard, in the manufacturing method of the present embodiment, the attitude of the planetary shaft main body 41 is restricted after the ring gears 22 and 23 and the sun gears 32 and 33 and the planetary gears 42 and 43 are engaged with each other. Since the demagnetization is performed, the inclination of the planetary shaft main body 41 can be suitably suppressed.

<Example of change of embodiment>
Note that the first embodiment can be implemented with the following modifications, for example.
In the first embodiment, the manufacturing method of magnetizing the sunshaft body 31 before being combined with each component is adopted. However, the sunshaft of the first assembly 91 or the second assembly 92 is assembled before the third assembly 93 is assembled. It is also possible to change to a manufacturing method in which the main body 31 is magnetized. In this case, in the first assembly 91 or the second assembly 92, the sunshaft main body 31 is magnetized while the planetary shaft main bodies 41 are held in a parallel posture by a separate jig.

In the first embodiment, the present invention is applied to the rotational linear motion conversion mechanism 1 having a structure in which force is transmitted between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4 through meshing of screws and gears. The manufacturing method of the present invention is applied to a rotary linear motion conversion mechanism having a structure in which force is transmitted only by screw engagement between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4. Can also be applied. Specifically, the manufacturing method of the present invention can be embodied as a manufacturing method of the rotational linear motion conversion mechanism by making the following changes to the manufacturing method of the first embodiment.
(A): Step E, step G, and step H are omitted.
(B): In step F, an assembly constituted by a combination of the first assembly 91 and the ring shaft main body 21 is assembled.
(C): In step I, the assembly assembled in the step (b) is demagnetized.
(D): In step J, the rotational linear motion conversion mechanism 1 is assembled by combining the assembly that has undergone step (c) with the front collar 51 and the back collar 52.

(Second Embodiment)
A second embodiment of the present invention will be described.
In the first embodiment, the manufacturing method of the present invention is embodied as a manufacturing method for restraining the attitude of each planetary shaft body 41 by magnetizing the sunshaft body 31. On the other hand, in the present embodiment, the present invention is embodied as a manufacturing method for restraining the posture of each planetary shaft body 41 by magnetizing the ring shaft body 21.

<Method for manufacturing rotational linear motion conversion mechanism>
The manufacturing method of the present embodiment is embodied by changing a part thereof as follows on the basis of the manufacturing method of the first embodiment.

[Step B] The ring shaft main body 21 is magnetized by the magnetizing device 71.
[Step C] The ring shaft body 21 is attached to a ring jig. The ring jig is configured as a jig having a structure similar to the basic jig 61 of the first embodiment. That is, a solar jig for fixing the ring shaft main body 21 and a planetary jig for supporting the end of each planetary shaft main body 41 are provided. Thereby, in a state where the ring shaft main body 21 is fixed to the sun jig of the ring jig, one of each planetary shaft main body 41 is in a state where the center line of the planetary shaft main body 41 and the center line of the planetary jig are aligned. Are attached to the corresponding planetary jigs, the planetary shaft bodies 41 are arranged at equal intervals around the center line of the ring shaft body 21 in a parallel posture.

[Step D] An assembly (fifth assembly) constituted by a combination of the ring shaft main body 21 and each planetary shaft main body 41 is assembled. That is, the fifth assembly is assembled by assembling each planetary shaft body 41 to the ring shaft body 21. Specifically, the following operations (a) and (b) are performed as operations for assembling the fifth assembly and operations associated therewith.
(A): The center line of the planetary shaft body 41 is aligned with the center line of the planetary jig of the ring jig, that is, the planetary shaft body 41 is attracted to the ring shaft body 21 in a parallel posture. The front shaft 41F of each planetary shaft body 41 is attached to the planetary jig.
(B): In accordance with the operation of (a), the female screw 24 of the ring shaft main body 21 and the male screw 44 of each planetary shaft main body 41 are engaged, and the front ring gear 22 and each front planetary gear 42 are engaged.

[Step E] An assembly (sixth assembly) constituted by a combination of the fifth assembly and the front ring gear 22 is assembled. That is, the sixth assembly is assembled by assembling the front ring gear 22 to the fifth assembly. Specifically, the sixth assembly is assembled through the following operations (a) and (b).
(A): The front ring gear 22 is arranged at a position where the center line of the ring shaft main body 21 and the center line of the ring shaft main body 21 are aligned on the back side of the fifth assembly.
(B): The front ring gear 22 and the front planetary gears 42 are engaged with each other.
(C): The front ring gear 22 is fixed to the ring shaft main body 21 by press-fitting into the main body gear portion 21B.

[Step F] An assembly (seventh assembly) constituted by a combination of the sixth assembly and the sunshaft body 31 is assembled. That is, the seventh assembly is assembled by assembling the sunshaft body 31 to the sixth assembly. Specifically, the seventh assembly is assembled through the following operations (a) and (b).
(A): The sun shaft main body 31 is disposed at a position where the center line of the ring shaft main body 21 and the center line of the ring shaft main body 21 are aligned on the back side of the sixth assembly.
(B): The male screw 34 of the sun shaft main body 31 is engaged with the male screw 44 of each planetary shaft main body 41 and screwed to a predetermined position.

[Step G] The gear assembly 99 is assembled by combining the rear ring gear 23, the rear sun gear 33, and the respective rear planetary gears 43.
[Step H] An assembly (eighth assembly) constituted by a combination of the seventh assembly and the gear assembly 99 is assembled. That is, the eighth assembly is assembled by assembling the gear assembly 99 to the seventh assembly.

[Step I] The ring shaft body 21 of the eighth assembly is demagnetized by the demagnetizer 72.
[Step J] An assembly (rotational linear motion conversion mechanism 1) constituted by a combination of the eighth assembly, the front collar 51, and the rear collar 52 is assembled. That is, the rotary linear motion conversion mechanism 1 is assembled by assembling the front collar 51 and the rear collar 52 to the eighth assembly.

<Effect of embodiment>
As described above in detail, according to the method for manufacturing the rotational linear motion conversion mechanism according to the second embodiment, effects similar to the effects (1) to (8) according to the first embodiment can be obtained. It becomes like this.

<Example of change of embodiment>
Note that the second embodiment can be implemented with modifications as shown below, for example.
In the second embodiment, the manufacturing method of magnetizing the ring shaft main body 21 before being combined with each component is adopted. However, before the seventh assembly is assembled, the ring shaft main body 21 of the fifth assembly or the sixth assembly is used. The manufacturing method can be changed to magnetize. In this case, in the fifth assembly or the sixth assembly, the ring shaft main body 21 is magnetized while the planetary shaft main bodies 41 are held in a parallel posture by a separate jig.

In the second embodiment, the present invention is applied to the rotational linear motion conversion mechanism 1 having a structure in which force is transmitted between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4 through meshing of screws and gears. The manufacturing method of the present invention is applied to a rotary linear motion conversion mechanism having a structure in which force is transmitted only by screw engagement between the ring shaft 2 and the sun shaft 3 and each planetary shaft 4. Can also be applied. Specifically, the manufacturing method of the present invention can be embodied as a manufacturing method of the rotating linear motion conversion mechanism by making the following changes to the manufacturing method of the second embodiment.
(A): Step E, step G, and step H are omitted.
(B): In step F, an assembly constituted by a combination of the fifth assembly and the sunshaft body 31 is assembled.
(C): In step I, the assembly assembled in the step (b) is demagnetized.
(D): In step J, the rotational linear motion conversion mechanism 1 is assembled by combining the assembly that has undergone step (c) with the front collar 51 and the back collar 52.

(Other embodiments)
Other elements that can be changed in common with each of the above-described embodiments are shown below.
In each of the above embodiments, the fourth assembly 94 is assembled through a combination of the third assembly 93 and the gear assembly 99. However, the assembly procedure of the fourth assembly 94 is, for example, any of the following (A) to (C) You can also change it.
(A) The fourth assembly 94 is assembled by assembling the rear ring gear 23, the rear sun gear 33, and the respective rear planetary gears 43 to the third assembly 93 individually.
(B) The 4th assembly 94 is assembled by assembling the assembly comprised by the combination of the back surface ring gear 23 and each back surface planetary gear 43, and the back surface sun gear 33 to the 3rd assembly 93 separately.
(C) The fourth assembly 94 is assembled by assembling the assembly constituted by the combination of the rear sun gear 33 and each rear planetary gear 43 and the rear ring gear 23 to the third assembly 93 individually.

  -The rotation linear motion conversion mechanism used as the application object of this invention is not restricted to the rotation linear motion conversion mechanism of the structure illustrated in each said embodiment. In short, force is transmitted between the shafts of the ring shaft and the male shaft of the sun shaft and the male screw of the planetary shaft, and the planetary shaft is driven by the planetary shaft accompanying the rotational movement of one of the ring shaft and the sun shaft. The present invention can be embodied as a method of manufacturing any rotary linear motion conversion mechanism that linearly moves the other of the ring shaft and the sun shaft.

The perspective view which shows the perspective structure of a rotation linear motion conversion mechanism about 1st Embodiment which actualized the manufacturing method of the rotation linear motion conversion mechanism concerning this invention. The perspective view which shows the internal structure about the rotation linear motion conversion mechanism of the embodiment. (A) Sectional drawing which shows the cross-section along the centerline about the ring shaft which comprises the rotation linear motion conversion mechanism of the embodiment. (B) Sectional drawing which shows the cross-section of the state which decomposed | disassembled the part about the ring shaft. (A) The front view which shows the front structure about the sun shaft which comprises the rotation linear motion conversion mechanism of the embodiment. (B) The front view which shows the front structure of the state which decomposed | disassembled about the sun shaft. (A) The front view which shows the front structure about the planetary shaft which comprises the rotation linear motion conversion mechanism of the embodiment. (B) The front view which shows the front structure of the state which decomposed | disassembled one part about the planetary shaft. (C) Sectional drawing which shows the cross-sectional structure along the centerline about the back planetary gear which comprises the planetary shaft. Sectional drawing which shows the cross-section along the centerline about the rotation linear motion conversion mechanism of the embodiment. Sectional drawing which shows the cross-section along the DA-DA line | wire of FIG. 6 about the rotation linear motion conversion mechanism of the embodiment. Sectional drawing which shows the cross-section along the DB-DB line | wire of FIG. 6 about the rotation linear motion conversion mechanism of the embodiment. Sectional drawing which shows the cross-section along the DC-DC line of FIG. 6 about the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process A about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process B about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process C about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. (A) The front view which shows the front structure about the basic jig used in the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. (B) Sectional drawing which shows the cross-section along the DD-DD line of FIG. 13 (A) about the basic jig | tool. Process drawing which shows the operation | work aspect in process D about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process E about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in the process F about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in the process G about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process H about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process I about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment. Process drawing which shows the operation | work aspect in process J about the manufacturing method of the rotation linear motion conversion mechanism of the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotary linear motion conversion mechanism, 2 ... Ring shaft, 21 ... Ring shaft main body, 21A ... Main body screw part, 21B ... Main body gear part, 21C ... Main body gear part, 22 ... Front ring gear, 23 ... Rear ring gear, 24 ... female screw, 3 ... sun shaft, 31 ... sun shaft main body, 31A ... main body screw portion, 31B ... main body gear portion, 31C ... main body gear portion, 32 ... front sun gear, 33 ... rear sun gear, 34 ... male screw, 4 ... planetary shaft , 41 ... Planetary shaft main body, 41A ... Main body screw part, 41B ... Main body gear part, 41F ... Front side shaft, 41R ... Rear side shaft, 42 ... Front planetary gear, 43 ... Rear planetary gear, 43H ... Bearing hole, 44 ... Male screw, 51 ... front collar, 51A ... bearing, 51H ... oil hole, 52 ... back collar, 52A ... bearing, 53 ... Ring, 61 ... basic jig, 62 ... sun jig, 62H ... insertion hole, 63 ... planetary jig, 63H ... support hole, 64 ... gear jig, 71 ... magnetizing device, 72 ... demagnetizing device, 91 ... 1st assembly, 92 ... 2nd assembly, 93 ... 3rd assembly, 94 ... 4th assembly, 99 ... Gear assembly.

Claims (10)

An annular shaft having a space extending in the axial direction, a solar shaft disposed inside the annular shaft, and a plurality of planetary shafts disposed around the solar shaft;
The annular shaft is configured to include an annular shaft body having an internal thread;
The sun axis is configured including a sun axis body having a male thread;
The planetary shaft is configured including a planetary shaft body having a male screw;
The internal thread of the annular shaft body meshes with the external thread of the planetary shaft body;
The male screw of the sun shaft main body and the male screw of the planetary shaft main body mesh with each other;
And a rotational linear motion conversion mechanism configured such that the other of the annular axis and the sun axis linearly moves through the planetary motion of the planetary axis accompanying the rotational motion of one of the annular axis and the sun axis. about,
Manufacturing is performed including the following first step, second step, and third step. “First step of magnetizing the solar axis body”
“A set composed of a combination of the solar axis body and the planetary axis body, with the attitude of the planetary axis body in which the centerline of the planetary axis body is parallel to the centerline of the solar axis body as a reference attitude The second step of assembling the first aggregate with the body as the first aggregate and holding the planetary shaft main body in the reference posture after the first step "
“Third step of assembling the second assembly in a state where the solar shaft main body is magnetized, with the assembly formed by the combination of the first assembly and the annular shaft main body as a second assembly”
A method of manufacturing a rotating linear motion conversion mechanism. An annular shaft having a space extending in the axial direction, a solar shaft disposed inside the annular shaft, and a plurality of planetary shafts disposed around the solar shaft;
The annular shaft is configured to include an annular shaft body having an internal thread;
The sun axis is configured including a sun axis body having a male thread;
The planetary shaft is configured including a planetary shaft body having a male screw;
The internal thread of the annular shaft body meshes with the external thread of the planetary shaft body;
The male screw of the sun shaft main body and the male screw of the planetary shaft main body mesh with each other;
And a rotational linear motion conversion mechanism configured such that the other of the annular axis and the sun axis linearly moves through the planetary motion of the planetary axis accompanying the rotational motion of one of the annular axis and the sun axis. about,
The manufacturing is performed including the following first step, second step and third step. “Based on the attitude of the planetary shaft body in which the centerline of the planetary shaft body is parallel to the centerline of the solar shaft body. As a posture, an assembly formed by a combination of the sun shaft main body and the planetary shaft main body is used as a first assembly, and the first assembly is assembled in a state where the planetary shaft main body is held in the reference posture. Process "
“Second Step of Magnetizing the Solar Axis Body of the First Assembly”
“Third step of assembling the second assembly in a state where the solar shaft main body is magnetized, with the assembly formed by the combination of the first assembly and the annular shaft main body as a second assembly”
A method of manufacturing a rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 1 or 2,
The annular shaft is configured to include the annular shaft body and an internal annular gear;
The sun shaft is configured including the sun shaft body and external sun gear;
The planetary shaft is configured including the planetary shaft body and an external planetary gear;
The annular gear includes a first annular gear provided at one end of the annular shaft main body and a second annular gear provided at the other end of the annular shaft main body,
As the sun gear, comprising a first sun gear provided at one end of the sun shaft main body and a second sun gear provided at the other end of the sun shaft main body,
The planetary gear includes a first planetary gear provided at one end of the planetary shaft main body and a second planetary gear provided at the other end of the planetary shaft main body,
The first annular gear is formed separately from the annular shaft body;
The second sun gear is formed separately from the sun shaft body;
The second planetary gear is formed separately from the planetary shaft body;
The first annular gear meshes with the first planetary gear,
The second annular gear and the second planetary gear mesh with each other;
Meshing of the first sun gear and the first planetary gear;
About the rotational linear motion conversion mechanism configured as a requirement that the second sun gear and the second planetary gear mesh with each other,
The manufacturing is performed including the following fourth step. “A set composed of a combination of the second set and the second planetary gear is defined as a third set, and the solar shaft body is magnetized. Fourth step of assembling the third assembly "
A method of manufacturing a rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 1 or 2,
The rotation linear motion conversion mechanism is manufactured including the next fifth step. “Fifth step of demagnetizing the solar shaft body after the third step”
A method of manufacturing a rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 3,
The rotational linear motion conversion mechanism is manufactured including the following sixth step. “The first annular gear, the first sun gear, and the first planetary gear are in mesh with each other and the second annular gear. And a sixth step of demagnetizing the sun shaft body for the third aggregate in a state where the second sun gear and the second planetary gear are engaged with each other.
A method of manufacturing a rotating linear motion conversion mechanism. An annular shaft having a space extending in the axial direction, a solar shaft disposed inside the annular shaft, and a plurality of planetary shafts disposed around the solar shaft;
The annular shaft is configured to include an annular shaft body having an internal thread;
The sun axis is configured including a sun axis body having a male thread;
The planetary shaft is configured including a planetary shaft body having a male screw;
The internal thread of the annular shaft body meshes with the external thread of the planetary shaft body;
The male screw of the sun shaft main body and the male screw of the planetary shaft main body mesh with each other;
And a rotational linear motion conversion mechanism configured such that the other of the annular axis and the sun axis linearly moves through the planetary motion of the planetary axis accompanying the rotational motion of one of the annular axis and the sun axis. about,
Manufacturing is performed including the following first step, second step and third step. “First step of magnetizing the annular shaft body”
“A configuration of the planetary shaft main body is a combination of the annular shaft main body and the planetary shaft main body, with the attitude of the planetary shaft main body in which the centerline of the planetary shaft main body is parallel to the centerline of the annular shaft main body as a reference posture. As a first assembly, a second step of assembling the first assembly with the planetary shaft body held in the reference posture after the first step "
“Third step of assembling the second assembly in a state in which the annular shaft body is magnetized, with the assembly formed by the combination of the first assembly and the sun shaft body as a second assembly”
A method of manufacturing a rotating linear motion conversion mechanism. An annular shaft having a space extending in the axial direction, a solar shaft disposed inside the annular shaft, and a plurality of planetary shafts disposed around the solar shaft;
The annular shaft is configured to include an annular shaft body having an internal thread;
The sun axis is configured including a sun axis body having a male thread;
The planetary shaft is configured including a planetary shaft body having a male screw;
The internal thread of the annular shaft body meshes with the external thread of the planetary shaft body;
The male screw of the sun shaft main body and the male screw of the planetary shaft main body mesh with each other;
And a rotational linear motion conversion mechanism configured such that the other of the annular axis and the sun axis linearly moves through the planetary motion of the planetary axis accompanying the rotational motion of one of the annular axis and the sun axis. about,
The manufacturing is performed including the following first step, second step, and third step. “The posture of the planetary shaft body is such that the centerline of the planetary shaft body is parallel to the centerline of the annular shaft body. Assembling the first assembly in a state in which the planetary shaft main body is held in the reference posture, with the assembly composed of a combination of the annular shaft main body and the planetary shaft main body as a reference posture. First step "
“Second step of magnetizing the annular shaft body of the first assembly”
“Third step of assembling the second assembly in a state in which the annular shaft body is magnetized, with the assembly formed by the combination of the first assembly and the sun shaft body as a second assembly”
A method of manufacturing a rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 6 or 7,
The annular shaft is configured to include the annular shaft body and an internal annular gear;
The sun shaft is configured including the sun shaft body and external sun gear;
The planetary shaft is configured including the planetary shaft body and an external planetary gear;
The annular gear includes a first annular gear provided at one end of the annular shaft main body and a second annular gear provided at the other end of the annular shaft main body,
As the sun gear, comprising a first sun gear provided at one end of the sun shaft main body and a second sun gear provided at the other end of the sun shaft main body,
The planetary gear includes a first planetary gear provided at one end of the planetary shaft main body and a second planetary gear provided at the other end of the planetary shaft main body,
The first annular gear is formed separately from the annular shaft body;
The second sun gear is formed separately from the sun shaft body;
The second planetary gear is formed separately from the planetary shaft body;
The first annular gear meshes with the first planetary gear,
The second annular gear and the second planetary gear mesh with each other;
Meshing of the first sun gear and the first planetary gear;
About the rotational linear motion conversion mechanism configured as a requirement that the second sun gear and the second planetary gear mesh with each other,
The manufacturing is performed including the following fourth step. “A state in which the annular shaft body is magnetized, with an aggregate formed by a combination of the second aggregate and the second planetary gear as a third aggregate. 4th process of assembling the third assembly with
A method of manufacturing a rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 6 or 7,
The rotation linear motion conversion mechanism is manufactured including the following fifth step. “Fifth step of demagnetizing the annular shaft body after the third step”
A method of manufacturing a rotating linear motion conversion mechanism. In the manufacturing method of the rotation linear motion conversion mechanism according to claim 8,
The rotational linear motion conversion mechanism is manufactured including the following sixth step. “The first annular gear, the first sun gear, and the first planetary gear are in mesh with each other and the second annular gear. And a sixth step of demagnetizing the annular shaft body of the third aggregate in a state where the second sun gear and the second planetary gear are engaged with each other.
A method of manufacturing a rotating linear motion conversion mechanism.

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